Cancers of the upper aero-digestive tract, which includes the oral cavity, oropharynx, and esophagus, are associated with rising incidence and uniformly poor survival, primarily due to diagnosis at a late, incurable stage. While visual screening and biopsy are recommended for at-risk individuals, the standard white-light exam frequently misses areas of early neoplasia. Moreover, incomplete resection leads to frequent recurrence. There is an important need for new imaging tools to improve early diagnosis and to guide effective treatment. Optical molecular imaging provides a unique solution to greatly improve clinical outcome. Over the last 5 years, we have developed optically active contrast agents, delivery formulations, and imaging systems which provide the ability to monitor and quantify molecular, functional, and morphologic biomarkers of early neoplasia. In this renewal, we propose to solve the clinical and technical challenges needed to realize these potential advantages in one organ system - the upper aero-digestive tract. In Aim 1, we will optimize and translate contrast agents and imaging systems for early diagnosis of intraepithelial neoplasia, culminating with pilot in vivo studies to assess sensitivity and specificity. Once lesions are identified, neoplastic tissue must be completely resected to prevent progression or recurrence. In Aim 2, we will develop molecular imaging systems to enable image-guided therapy of intra-epithelial neoplasia. We will develop and test guidance approaches for: image-guided open surgery in the oral cavity; image-guided endoscopic resection in the esophagus; and image-guided robotic surgery in the oropharynx. In the next 20 years, the number of cancer deaths worldwide will double. As successful cervical cancer screening programs indicate, early detection and treatment using optical molecular imaging could reduce cancer mortality and incidence by 4 times--a result equal to or better than any blockbuster drug! The translational bioengineering studies proposed here will result in low-cost, portable tools to improve early detection and image-guided therapy of intraepithelial neoplasia in the upper aero-digestive tract, providing a foundation to extend these tools to other organ sites.